On the functional equation $$f(x+y)=f(x)+f(y)$$f(x+y)=f(x)+f(y)

Monatshefte für Mathematik - An extension of the linearity of the continuous solutions of the functional equation $$f(x+y)=f(x)+f(y)$$ to measurable functions is presented.     

The Functional Equationf(x+y−xy)+f(xy)=f(x)+f(y)

Aequationes mathematicae -     

The matrix equationa(x∘y)=a(x)+a(x)a(y)+a(y)

Aequationes mathematicae -     

Eine Basis aller Zahlen und die unstetigen Lösungen der Funktionalgleichung:f(x+y)=f(x)+f(y)

Ohne Zusammenfassung     

On the system of functional equationsf(x + y) = f(x) + f(y) andf(xy) = p (x)f(y) + q(y)f(x)

Aequationes mathematicae -     

Sur l'équationf(x)f(y)f(−x−y)=g(x)g(y)g(−x−y)

Sans résumé

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Über die Funktionalgleichung f(f(x)*f(y))=f(x*y)

In this paper, the general solution of three functional equations occuring in interpolation theory are given in the general situation when variables belong to a semi-group with unit. We then specialize to some particular cases by specifying either the semi-group, or adding some regular properties like continuity or measurability.     

关于函数y=f(x)与y=|f(x)|

本文对函数 y=f ( x)与 y=|f ( x) |的部分性质进行了比较和分析 ,指出了它们性质上的区别与联系 .     

Über die Funktionalgleichungf(f(x)*f(y)) = f(x*y)

Ohne Zusammenfassung     

On the functional equation x + f(y + f(x))=y + f(x + f(y))

For an abelian group (G, + ,0) we consider the functional equation $$f : G \to G, x + f(y + f(x)) = y + f(x + f(y)) \quad (\forall x, y \in G), \quad\quad\qquad (1)$$ most times together with the condition $$f(0) = 0.\qquad\qquad\qquad\qquad\qquad (0)$$ Our main question is whether a solution of ${(1) \wedge (0)}$ must be additive, i.e., an endomorphism of G. We shall answer this question in the negative (Example 3.14) Rätz (Aequationes Math 81:300, 2011).     

关于π(x+y)≤π(x)+π(y)的一些研究结果

§ 1.　Introduction　　Indistributionofprimenumbersthereisamorecommonconjecturethanthatof“twinprimenumbers” :Ifdispelledbycongruencerelation ,thereisanunlimitednumberofprimenumbercon coursesofanygiventype .Forexample ,itisreasonabletobelievethatthereisanunlimitednumberofprimenumberconcoursescomposedofthreeasagroup ( {6k- 1 ,6k + 1 ,6k+ 5 }and {6k+ 1 ,6k+ 5 ,6k+ 7}) ,whichcanbenamedas“threeprimenumbers” .Isthereanunlimitednumberof“n primenumbers”suchas {p +k1 ,p +k2 ,… ,p+kn-1 },whichare…